[0001] Osteoporosis describes a group of diseases which arises from diverse etiologies,
but which are characterized by the net loss of bone mass per unit volume. The consequence
of this loss of bone mass and resulting bone fracture is the failure of the skeleton
to provide adequate support for the body. One of the most common types of osteoporosis
is associated with menopause. Most women lose from about 20% to about 60% of the bone
mass in the trabecular compartment of the bone within 3 to 6 years after the cessation
of menses. This rapid loss is generally associated with an increase of bone resorption
and formation. However, the resorptive cycle is more dominant and the result is a
net loss of bone mass. Osteoporosis is a common and serious disease among postmenopausal
women.
[0002] There are an estimated 25 million women in the United States alone who are afflicted
with this disease. The results of osteoporosis are personally harmful, and also account
for a large economic loss due to its chronicity and the need for extensive and long
term support (hospitalization and nursing home care) from the disease sequelae. This
is especially true in more elderly patients. Additionally, although osteoporosis is
generally not thought of as a life threatening condition, a 20% to 30% mortality rate
is related
to hip fractures in elderly women. A large percentage of this mortality rate can be
directly associated with postmenopausal osteoporosis.
[0003] The most vulnerable tissue in the bone to the effects of postmenopausal osteoporosis
is the trabecular bone. This tissue is often referred to as spongy or cancellous bone
and is particularly concentrated near the ends of the bone (near the joints) and in
the vertebrae of the spine. The trabecular tissue is characterized by small osteoid
structures which interconnect with each other, as well as the more solid and dense
cortical tissue which makes up the outer surface and central shaft of the bone. This
interconnected network of trabeculae gives lateral support to the outer cortical structure
and is critical to the biomechanical strength of the overall structure. In postmenopausal
osteoporosis, it is primarily the net resorption and loss of the trabeculae which
leads to the failure and fracture of bone. In light of the loss of the trabeculae
in the postmenopausal woman, it is not surprising that the most common fractures are
those associated with bones which are highly dependent on trabecular support, for
example, the vertebrae, the neck of the weight-bearing bones such as the femur and
the forearm. Indeed, hip fracture, collies fractures, and vertebral crush fractures
are hallmarks of postmenopausal osteoporosis.
[0004] The most generally accepted method for the treatment of postmenopausal osteoporosis
is estrogen replacement therapy. Although therapy is generally successful, patient
compliance with the therapy is low, primarily because estrogen treatment frequently
produces undesirable side effects. An additional method of treatment would be the
administration of a bisphosphonate compound, such as, for example, Fosamax® (Merck
& Co., Inc.).
[0005] Throughout premenopausal time, most women have less incidence of cardiovascular disease
than men of the same age. Following menopause, however, the rate of cardiovascular
disease in women slowly increases to match the rate seen in men. This loss of protection
has been linked to the loss of estrogen and, in particular, to the loss of estrogen's
ability to regulate the levels of serum lipids. The nature of estrogen's ability to
regulate serum lipids is not well understood, but evidence to date indicates that
estrogen can up regulate the low density lipid (LDL) receptors in the liver to remove
excess cholesterol. Additionally, estrogen appears to have some effect on the biosynthesis
of cholesterol, and other beneficial effects on cardiovascular health.
[0006] It has been reported in the literature that serum lipid levels in postmenopausal
women having estrogen replacement therapy return to concentrations found in the premenopausal
state. Thus, estrogen would appear to be a reasonable treatment for this condition.
However, the side effects of estrogen replacement therapy are not acceptable to many
women, thus limiting the use of this therapy. An ideal therapy for this condition
would be an agent which regulates serum lipid levels in a manner analogous to estrogen,
but which is devoid of the side effects and risks associated with estrogen therapy.
[0007] A number of structurally unrelated compounds are capable of interacting with the
estrogen receptor and producing unique in vivo profiles. Compounds with in vivo profiles
typical of a "pure" antagonist (for example, ICI 164,384) or of a relatively "pure"
agonist (for example, 17b-estradiol) represent opposite ends of a spectrum in this
classification. Between these two extremes lie the SERMs ("selective estrogen receptor
modulator"), characterized by clinical and/or preclinical selectivity as full or partial
agonists in certain desired tissues (for example, bone), and antagonists or minimal
agonists in reproductive tissues. Within this pharmacologic class, individual SERMs
may be further differentiated based on profiles of activity in reproductive tissues.
Raloxifene, a second generation SERM, displays potentially useful selectivity in uterine
tissue with apparent advantages over triphenylethylene-based estrogen receptor ligands.
As such, raloxifene appears to be well-suited at least for the treatment of postmenopausal
complications, including osteoporosis and cardiovascular disease. It is anticipated
that, as further advances are made in the pharmacology and molecular biology of estrogen
receptor active agents, further subclassifications of SERMs may evolve in the future
along with an increased understanding of the therapeutic utility of these novel classes
of estrogenic compounds.
[0008] The advancement of raloxifene, in particular, has been somewhat hampered by its physical
characteristics, both as to bioavailability and manufacturing. For example, raloxifene
is generally insoluble, which may affect bioavailability. Clearly, any improvement
in the physical characteristics of raloxifene and in closely related compounds would
potentially offer a more beneficial therapy and enhanced manufacturing capabilities.
[0009] Thus, it would be a significant contribution to the art to provide amorphous forms
of raloxifene and related compounds which have increased solubility, methods of preparation,
pharmaceutical formulations, and methods of use.
[0010] The present invention provides a compound of formula I
or a pharmaceutically acceptable salt or solvate thereof, in an amorphous form.
[0011] The present invention further provides pharmaceutical formulations containing a compound
of formula I.
[0012] Still further provided by way of the instant invention are processes for the preparation
of amorphous forms of the compound of formula I.
[0013] The instant invention also provides methods of use for the compound of formula I,
including the inhibition of bone loss or bone resorption.
[0014] The term "inhibit" includes its generally accepted meaning which includes prohibiting,
preventing, restraining, and slowing, stopping, or reversing progression, severity,
or ameliorating a resultant symptom or effect.
[0015] The compound of the current invention may be made according to established procedures,
such as those detailed in U.S. Patent Nos. 4,133,814, 4,418,068, and 4,380,635, and
European Patent Application 95306050.6, Publication No. 0699672, Kjell,
et al., filed August 30, 1995, published March 6, 1996, all of which are herein incorporated
by reference. In addition, the information disclosed in the published European Patent
Application number 0670162 Al, published on September 6, 1995, is herein incorporated
by reference. A crystalline form of raloxifene hydrochloride may be prepared by the
methods disclosed in the Example section,
infra.
[0016] The term "amorphous" includes a physical state which may be verified by x-ray diffraction
and other means including but not limited to observation with a polarized light microscope
and differential scanning calorimetry.
[0017] In general, the process starts with a benzo[b]thiophene having a 6-hydroxyl group
and a 2-(4-hydroxyphenyl) group. The starting compound is protected, acylated, and
deprotected to form the compound of formula I. Further examples of the preparation
of the compound of formula I are also provided in the references discussed above.
[0018] The compound of formula I according to the present invention is conveniently prepared
by a process which constitutes a further feature of the present invention, and which
comprises recovering a compound of formula I from a solution thereof under conditions
whereby an amorphous product is obtained.
[0019] The amorphous material of the instant invention was prepared by dissolving a crystalline
form of a compound of formula I in a suitable solvent or solvent mixture, such as,
for example, methanol and water, followed by recovery of the material by any suitable
means. Techniques which may be employed to recover an amorphous form of the compound
of formula I from the solution include those wherein the solvent is removed from the
solution, preferably rapidly, and the product deposited, and those wherein the product
is precipitated from a solution. Methods involving the use of these procedures which
have been found to be satisfactory include spray drying, roller drying, solvent precipitation,
rotary evaporation, and freeze drying. Particularly preferred for the practice of
the present invention is the method of spray drying.
[0020] Solvents which may be employed in the practice of the present invention will be chosen
according to the technique and conditions to be employed, and include water, methanol,
ethanol, and the like, including mixtures thereof, if desired.
[0021] The concentration of a compound of formula I in the solvent is advantageously as
high as possible, commensurate with an amorphous form of a compound of formula I being
obtained, with preferrable concentrations being in the range of from about 5 mg/ml
to about 40 mg/ml. The higher concentrations obtained will typically depend on the
solvent system employed in the preparation, and/or the presence or absence of povidone
(PVP) or hydroxypropyl-b-cyclodextrin (HPBCD). The solvents may, if desired, be heated
as an aid to solubility and solvent removal.
[0022] In general, the compound of formula I has sufficient heat stability to withstand
spray drying and the like, and accordingly, spray drying is the preferred method of
recovery. Spray drying systems may be operated in a known manner to obtain an amorphous
product essentially free from crystalline material as well as free from particulate
contaminants. Closed cycle spray drying systems in which the drying medium is recycled
are particularly safe and economic for use in obtaining the product of the present
invention.
[0023] The drying gas employed in the process may be air, but preferred for the use with
flammable solvents are inert gases such as, for example, nitrogen, argon and carbon
dioxide. Preferred would be nitrogen. The gas inlet temperature to the spray dryer
is chosen according to the solvent employed, but would be, for example, in the range
of from about 75 °C to about 150 °C.
[0024] The presence of the amorphous form of a compound of formula I was determined by observing
the material under a polarized light microscope, and determining if the material was
birefringent. If no birefringence was observed, the material was considered to be
amorphous.
[0025] A compound of formula I in accordance with the present invention is preferably essentially
free from the crystalline form of the material. Long term studies have indicated the
amorphous form of the instant invention is very stable. However, once recovered as
amorphous material, conversion to the crystalline form may be prevented by the addition
of any number of stabilizer materials known in the art, such as, for example, povidone,
hydroxypropyl methylcellulose (HPMC), hydroxypropylcellulose (HPC), polyethylene glycol
(PEG), hydroxypropyl-b-cyclodextrin (HPB), cyclodextrin, and the like.
[0026] Solubility of the amorphous form was demonstrated to be approximately 250 times greater
than the crystalline form. Advantages of increased solubility include but are not
limited to ease in processing the amorphous material, which includes equipment cleaning
issues; ease in formulation and delivery of the material, and the like.
[0027] A compound of formula I in an amorphous form may also be combined with a number of
other materials prior to or after spray drying, or otherwise processed to provide
amorphous material, which may in turn be further formulated for processing.
[0028] A Compounds of formula I which is amorphous has been demonstrated to have several
advantages, including but not limited to a high degree of bioavailability, as well
as being in a form for effective methods of administration.
[0029] The term "solvate" represents an aggregate that comprises one or more molecules of
the solute, such as a formula I compound, with one or more molecules of solvent. Although
the free-base form of the formula I compound can be used in the methods of the present
invention, it is preferred to prepare and use a pharmaceutically acceptable salt form.
The term "pharmaceutically acceptable salt" refers to either acid or base addition
salts which are known to be non-toxic and are commonly used in the pharmaceutical
literature. The pharmaceutically acceptable salts generally have enhanced solubility
characteristics compared to the compound from which they are derived, and thus are
often more amenable to formulation as liquids or emulsions. The compounds used in
the methods of this invention primarily form pharmaceutically acceptable acid addition
salts with a wide variety of organic and inorganic acids, and include the physiologically
acceptable salts which are often used in pharmaceutical chemistry. Such salts are
also part of this invention. Typical inorganic acids used to form such salts include
hydrochloric, hydrobromic, hydroiodic, nitric, sulfuric, phosphoric, hypophosphoric,
and the like. Salts derived from organic acids, such as aliphatic mono and dicarboxylic
acids, phenyl-substituted alkanoic acids, hydroxyalkanoic and hydroxyalkandioic acids,
aromatic acids, aliphatic and aromatic sulfonic acids, may also be used. Such pharmaceutically
acceptable salts thus include acetate, phenylacetate, trifluoroacetate, acrylate,
ascorbate, benzoate, chlorobenzoate, dinitrobenzoate, hydroxybenzoate, methoxybenzoate,
methylbenzoate, o-acetoxybenzoate, naphthalene-2-benzoate, bromide, isobutyrate, phenylbutyrate,
β-hydroxybutyrate, butyne-1,4-dioate, hexyne-1,4-dioate, caproate, caprylate, chloride,
cinnamate, citrate, formate, fumarate, glycolate, heptanoate, hippurate, lactate,
malate, maleate, hydroxymaleate, malonate, mandelate, mesylate, nicotinate, isonicotinate,
nitrate, oxalate, phthalate, terephthalate, phosphate, monohydrogenphosphate, dihydrogenphosphate,
metaphosphate, pyrophosphate, propiolate, propionate, phenylpropionate, salicylate,
sebacate, succinate, suberate, sulfate, bisulfate, pyrosulfate, sulfite, bisulfite,
sulfonate, benzenesulfonate,
p-bromophenylsulfonate, chlorobenzenesulfonate, ethanesulfonate, 2-hydroxyethanesulfonate,
methanesulfonate, naphthalene-1-sulfonate, naphthalene-2-sulfonate,
p-toluenesulfonate, xylenesulfonate, tartarate, and the like. A preferred salt is the
hydrochloride salt.
[0030] The pharmaceutically acceptable acid addition salts are typically formed by reacting
a compound of formula I with an equimolar or excess amount of acid. The reactants
are generally combined in a mutual solvent such as diethyl ether or ethyl acetate.
The salt normally precipitates out of solution within about one hour to 10 days and
can be isolated by filtration, or the solvent can be stripped off by conventional
means. The present invention further provides for pharmaceutically acceptable formulations
for administering to a mammal, including humans, in need of treatment, which comprises
an effective amount of a compound of formula I and a pharmaceutically acceptable diluent
or carrier.
[0031] As used herein, the term "effective amount" means an amount of compound of the present
invention which is capable of inhibiting, alleviating, ameliorating, treating, or
preventing further symptoms in mammals, including humans, suffering from estrogen
deprivation, for example, menopause or ovariectomy, or inappropriate estrogen stimulation
such as uterine fibrosis or endometriosis, or suffering from aortal smooth muscle
cell profileration or restenosis. In the case of estrogen-dependent cancers, the term
"effective amount" means the amount of compound of the present invention which is
capable of alleviating, ameliorating, inhibiting cancer growth, treating, or preventing
the cancer and/or its symptoms in mammals, including humans.
[0032] By "pharmaceutically acceptable formulation" it is meant that the carrier, diluent,
excipients and salt must be compatible with the active ingredient (a compound of formula
I) of the formulation, and not be deleterious to the recipient thereof. Pharmaceutical
formulations can be prepared by procedures known in the art. For example, the compound
of this invention can be formulated with common excipients, diluents, or carriers,
and formed into tablets, capsules, and the like. Examples of excipients, diluents,
and carriers that are suitable for such formulations include the following: fillers
and extenders such as starch, sugars, mannitol, and silicic derivatives; binding agents
such as carboxymethyl cellulose and other cellulose derivatives, alginates, gelatin,
and polyvinyl pyrrolidone; moisturizing agents such as glycerol; disintegrating agents
such as povidone, sodium starch glycolate, sodium carboxymethylcellulose, agar agar,
calcium carbonate, and sodium bicarbonate; agents for retarding dissollution such
as paraffin; resorption accelerators such as quaternary ammonium compounds; surface
active agents such as cetyl alcohol, glycerol monostearate; adsorptive carriers such
as kaolin and bentonite; and lubricants such as talc, calcium and magnesium stearate
and solid polyethylene glycols. Final pharmaceutical forms may be: pills, tablets,
powders, lozenges, sachets, cachets, or sterile packaged powders, and the like, depending
on the type of excipient used.
[0033] Additionally, the compound of this invention is well suited to formulation as sustained
release dosage forms. The formulations can also be so constituted that they release
the active ingredient only or preferably in a particular part of the intestinal tract,
possibly over a period of time. Such formulations would involve coatings, envelopes,
or protective matrices which may be made from polymeric substances or waxes.
[0034] The particular dosage of a compound of formula I required to treat, inhibit, or prevent
the symptoms and/ or disease of a mammal, including humans, suffering from the above
maladies according to this invention will depend upon the particular disease, symptoms,
and severity. Dosage, routes of administration, and frequency of dosing is best decided
by the attending physician. Generally, accepted and effective doses will be from 15mg
to 1000mg, and more typically from 15mg to 80mg. Such dosages will be administered
to a patient in need of treatment from one to three times each day or as often as
needed for efficacy, and for periods of at least two months, more typically for at
least six months, or chronically.
[0035] As a further embodiment of the invention, the compound of formula I may be administered
along with an effective amount of an additional therapeutic agent, including but not
limited to estrogen, progestin, benzothiophene compounds having including raloxifene,
naphthyl compounds having antiestrogen activity, bisphosphonate compounds such as
alendronate and tiludronate, parathyroid hormone (PTH), including truncated and/or
recombinant forms of PTH such as, for example, PTH (1-34), calcitonin, bone morphogenic
proteins (BMPs), or combinations thereof. The different forms of these additional
therapeutic agents available as well as the various utilities associated with same
and the applicable dosing regimens are well known to those of skill in the art.
[0036] Various forms of estrogen and progestin are commercially available. As used herein,
the term "estrogen" includes compounds having estrogen activity and estrogen-based
agents. Estrogen compounds useful in the practice of the present invention include,
for example, estradiol estrone, estriol, equilin, equilenin, estradiol cypionate,
estradiol valerate, ethynyl estradiol, polyestradiol phosphate, estropipate, diethylstibestrol,
dienestrol, chlorotrianisene, and mixtures thereof. Estrogen-based agents, include,
for example, 17-a-ethynyl estradiol (0.01-0.03 mg/day), mestranol (0.05-0.15 mg/day),
and conjugated estrogenic hormones such as Premarin® (Wyeth-Ayerst; 0.2-2.5 mg/day).
As used herein, the term "progestin" includes compounds having progestational activity
such as, for example, progesterone, norethynodrel, norgestrel, megestrol acetate,
norethindrone, progestin-based agents, and the like. Progestin-based agents include,
for example, medroxyprogesterone such as Provera® (Upjohn; 2.5-10 mg/day), norethylnodrel
(1.0-10.0 mg/day), and norethindrone (0.5-2.0 mg/day). A preferred estrogen-based
compound is Premarin®, and norethylnodrel and norethindrone are preferred progestin-based
agents. The method of administration of each estrogen- and progestin-based agent is
consistent with that known in the art.
[0037] The formulations which follow are given for purposes of illustration and are not
intended to be limiting in any way. The total active ingredients in such formulations
comprises from 0.1% to 99.9% by weight of the formulation. The term "active ingredient"
means a compound of formula I.
Formulation 1: Gelatin Capsules |
Ingredient |
Quantity (mg/capsule) |
Active Ingredient |
0.1-1000 |
Starch NF |
0-500 |
Starch flowable powder |
0-500 |
Silicone fluid 350 centistokes |
0-15 |
The ingredients are blended, passed through a No. 45 mesh U.S. sieve, and filled
into hard gelatin capsules.
Formulation 2: Tablets |
Ingredient |
Quantity (mg/tablet) |
Active Ingredient |
2.5-1000 |
Starch |
10-50 |
Cellulose, microcrystalline |
10-20 |
Polyvinylpyrrolidone (as 10% solution in water) |
5 |
Sodium carboxymethylcellulose |
5 |
Magnesium stearate |
1 |
Talc |
1-5 |
[0038] The active ingredient, starch, and cellulose are passed through a No. 45 mesh U.S.
sieve and mixed thoroughly. The solution of polyvinylpyrrolidone is mixed with the
resultant powders which are then passed through a No. 14 mesh U.S. sieve. The granules
thus produced are dried at 50-60 °C and passed through a No. 18 mesh U.S. sieve. The
sodium carboxymethylcellulose, magnesium stearate, and talc, previously passed through
a No. 60 mesh U.S. sieve, are added to the above granules and thoroughly mixed. The
resultant material is compressed in a tablet forming machine to yield the tablets.
Formulation 3: Suppositories |
Ingredient |
Weight |
Active ingredient |
150 mg |
Saturated fatty acid glycerides |
3000mg |
[0039] The active ingredient is passed through a No. 60 mesh U.S. sieve and suspended in
the fatty acid glycerides which had previously heated to their melting point. The
mixture is poured into a suppository mold and allowed to cool.
[0040] The following examples and preparations are provided to better elucidate the practice
of the present invention and should not be interpreted in any way as to limit the
scope of same. Those skilled in the art will recognize that various modifications
may be made while not departing from the spirit and scope of the invention. All publications
and patent applications mentioned in the specification are indicative of the level
of those skilled in the art to which this invention pertains.
[0041] NMR data for the following Examples were generated on a GE 300 MHz NMR instrument,
and anhydrous d-6 DMSO was used as the solvent unless otherwise indicated.
[0042] All experiments were run under positive pressure of dry nitrogen. All solvents and
reagents were used as obtained. The percentages are generally calculated on a weight
(w/w) basis; except for HPLC solvents which are calculated on a volume (v/v) basis.
Proton nuclear magnetic resonance (
1H NMR) spectra were obtained on a Bruker AC-300 FTNMR spectrometer at 300.135 MHz.
Melting points were determined by differential scanning calorimetry (DSC) in a TA
Instrument DCS 2920 using a closed cell and a heating rate of 2°C/minute. The reactions
were generally monitored for completion using high performance liquid chromatography
(HPLC). The X-ray powder diffraction spectra were obtained in a Siemens D5000 X-Ray
Powder Diffraktometer, using copper radiation and a Si(Li) detector. Some reactions
were monitored using a Zorbax Rx-C8 column, (25 cm x 4.6 mm ID, 5 m particle) eluting
with a mixture of 60 mM phosphate (KH
2PO
4) and 10 mM octanesulfonate (pH 2.0)/ acetonitrile (60:40).
[0043] The acylation, dealkylation, or acylation/dealkylation reactions are also monitored
for completion by HPLC. A sample of the reaction mixture was assayed using a Zorbax
Rx-C8 column, (25 cm x 4.6 mm ID, 5 m particle), eluting with a gradient as shown
below:
GRADIENT SOLVENT SYSTEM |
Time (min.) |
A (%) |
B (%) |
0 |
60 |
40 |
5 |
60 |
40 |
10 |
45 |
55 |
20 |
38 |
62 |
25 |
45 |
55 |
32 |
45 |
55 |
37 |
60 |
40 |
42 |
60 |
40 |
A: 0.05 M HClO4 (pH=2.0) |
B: acetonitrile |
[0044] The reaction mixture was analyzed by diluting a 0.1 to 0.2 mL sample to 50 mL with
a 60:40 mixture of A/B. Similarly, the mother liquor of the recrystallizations was
sampled in a similar manner.
[0045] The amount (percentages) of 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]
benzo[b]thiophene hydrochloride in the crystalline material (potency) was determined
by the following method. A sample of the crystalline solid (5 mg) was weighed into
a 100-mL volumetric flask, and dissolved in a 70/30 (v/v) mixture of 75 mM potassium
phosphate buffer (pH 2.0) and acetonitrile. An aliquot of this solution (10 m L) was
assayed by high performance liquid chromatography, using a Zorbax Rx-C8 column (25
cm x 4.6 mm ID, 5 m particle) and UV detection (280 nm). The following gradient solvent
system is used:
Gradient Solvent System (Potency) |
time (min.) |
A (%) |
B (%) |
0 |
70 |
30 |
12 |
70 |
30 |
14 |
25 |
75 |
16 |
70 |
30 |
25 |
70 |
30 |
A: 75 mM KH2PO4 buffer (pH 2.0) |
B: acetonitrile |
[0046] The percentage of 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]benzo[b]thiophene
hydrochloride in the sample is calculated using the peak area, slope (m), and intercept
(b) of the calibration curve with the following equation:
[0047] The amount (percentage) of solvent, such as methanol, ethanol, or 1,2-dichloroethane,
present in the crystalline material is determined by gas chromatography. A sample
of the crystalline solid (50 mg) was weighed into a 10-mL volumetric flask, and dissolved
in a solution of 2-butanol (0.025 mg/mL) in dimethylsulfoxide. A sample of this solution
was analyzed on a gas chromatograph using a DB Wax column (30 m x 0.53 mm ID, 1 m
particle), with a column flow of 10 mL/min and flame ionization detection. The column
temperature was heated from 35°C to 230°C over a 12 minute period. The amount of solvent
was determined by comparison to the internal standard (2-butanol), using the following
formula:
wherein:
C = ratio of solvent in sample
D = average ratio of standard for specific solvent
E = average weight of standard
F = weight of sample (mg)
G = volume of sample (10 mL)
H = volume of standard (10,000 mL)
I = purity of standard (%)
Preparation 1
6-Methoxy-2-(4-methoxyphenyl)benzo[b]thiophene
[0048] A solution of 3-methoxybenzenethiol (100 grams) and potassium hydroxide (39.1 grams)
in water (300 mL) was added to denatured ethanol (750 mL), and the resulting mixture
cooled to about 0°C. The cold mixture was treated with 4'-methoxyphenacyl bromide
(164 grams) in several small portions. Upon complete addition, the mixture was cooled
for an additional ten minutes, then allowed to warm to room temperature. After three
hours, the mixture was concentrated
in vacuo, and the residue treated with water (200 mL). The resulting mixture was treated with
ethyl acetate, and the phases were separated. The organic phase was washed with water
(2x), sodium bicarbonate solution (2x), and sodium chloride solution (2x). The organic
phase was then dried over magnesium sulfate, filtered, and evaporated to dryness
in vacuo to give 202 grams of a-(3-methoxyphenylthio)-4-methoxyacetophenone. This crude product
was crystallized from methanol and washed with hexane to give 158 grams. Melting point
53°C.
[0049] Polyphosphoric acid (930 grams) was heated to 85°C and treated with the intermediate
product from above (124 grams) in small portions over 30 minutes. Upon complete addition,
the resulting mixture was stirred at 90°C. After an additional 45 minutes, the reaction
mixture was allowed to cool to room temperature. This mixture was treated with crushed
ice while the mixture was cooled in an ice bath. The resulting mixture was treated
with water (100 mL) producing a light pink precipitate. The precipitate was isolated
by filtration, washed with water and methanol, and dried
in vacuo at 40°C to give 119 grams of 6-methoxy-2-(4-methoxyphenyl) benzo[b]thiophene. This
crude product was slurried in hot methanol, filtered, and washed with cold methanol.
The resulting solid material was recrystallized from ethyl acetate (4 liters), filtered,
washed with hexane, and dried
in vacuo to 68 grams of the title compound. Melting point 187-190.5°C.
Preparation 2
Ethyl 4-(2-Piperidinylethoxy)benzoate
[0050] A mixture of ethyl 4-hydroxybenzoate (8.31 g), 1-(2-chloroethyl)piperidine monohydrochloride
(10.13 g), potassium carbonate (16.59 g), and methyl ethyl ketone (60 mL) was heated
to 80°C. After one hour, the mixture was cooled to about 55°C and treated with additional
1-(2-chloroethyl)piperidine mono-hydrochloride (0.92 g). The resulting mixture was
heated to 80°C. The reaction was monitored by thin layer chromatography (TLC), using
silicagel plates and ethyl acetate/acetonitrile/ triethylamine (10:6:1, v/v). Additional
portions of 1-(2-chloroethyl)piperidine hydrochloride are added until the starting
4-hydroxybenzoate ester is consumed. Upon complete reaction, the reaction mixture
was treated with water (60 mL) and allowed to cool to room temperature. The aqueous
layer was discarded and the organic layer concentrated in
vacuo at 40°C and 40 mm Hg. The resulting oil was used in the next step without further
purification.
Preparation 3
4-(2-Piperidinylethoxy)benzoic Acid Hydrochloride
[0051] A solution of the compound prepared as described in Preparation 2 (about 13.87 g)
in methanol (30 mL) was treated with 5 N sodium hydroxide (15 mL), and heated to 40°C.
After
4 1/2 hours, water (40 mL) was added. The resulting mixture was cooled to 5-10°C,
and concentrated hydrochloric acid (18 mL) was added slowly. The title compound crystallized
during acidification. This crystalline product was collected by filtration, and dried
in vacuo at 40-50°C to give 83% yield of the title compound. Melting point 270-271°C.
Preparation 4
6-Methoxy-2-(4-methoxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]-benzo[b]thiophene
Hydrochloride
[0052] A mixture of the compound prepared as described in Preparation 1 (8.46 grams) and
the acid chloride prepared as described in Preparation 3 (10.0 grams) in methylene
chloride (350 mL) was cooled to about 20-25°C. The cool mixture was treated with boron
trichloride (2.6 mL), and the resulting mixture mechanically stirred. The reaction
was monitored by HPLC using the assay described above. After 85 minutes, the
in situ HPLC yield based on a 6-methoxy-2-(4-methoxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]benzo[b]thiophene
standard was 88%.
Preparation 5
6-Hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]-benzo[b]thiophene
Hydrochloride 1,2-Dichloroethane Solvate
(Crystal Form I)
[0053] A solution of 6-methoxy-2-(4-methoxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]benzo[b]thiophene
hydrochloride (2.0 g) in 1,2-dichloroethane (20 mL) was treated with boron trichloride
(2.0 mL). The resulting mixture was stirred at 35°C for about 18 hours. A mixture
of ethanol and methanol (10 mL, 95:5, 3A) was treated with the reaction mixture from
above, causing the alcoholic mixture to reflux. Upon complete addition, the resulting
crystalline slurry was stirred at 25°C. After one hour, the crystalline product was
filtered, washed with cold ethanol (10 mL), and dried at 40°C
in vacuo to give 1.78 g of the title compound. The X-ray powder diffraction pattern is identical
to that reported in Table 1.
Potency: 80.2%
1,2-Dichloroethane: 7.5% (gas chromatography)
Table 1.
X-ray Diffraction Pattern for Crystal Form 1. |
d-line spacing |
I/Io |
(Angstroms) |
(x100) |
16.1265 |
3.80 |
10.3744 |
8.63 |
8.3746 |
5.29 |
7.9883 |
36.71 |
7.2701 |
5.06 |
6.5567 |
70.77 |
6.2531 |
6.79 |
5.5616 |
24.05 |
5.3879 |
100.00 |
5.0471 |
89.64 |
4.7391 |
85.96 |
4.6777 |
39.36 |
4.6332 |
62.60 |
4.5191 |
77.56 |
4.2867 |
36.82 |
4.2365 |
41.66 |
4.1816 |
49.60 |
4.0900 |
11.28 |
3.9496 |
11.85 |
3.7869 |
36.25 |
3.7577 |
56.16 |
3.6509 |
40.62 |
3.5751 |
15.65 |
3.5181 |
21.52 |
3.4964 |
18.53 |
3.4361 |
33.60 |
3.3610 |
6.21 |
3.3115 |
4.95 |
3.2564 |
7.36 |
3.2002 |
3.80 |
3.1199 |
15.77 |
3.0347 |
14.84 |
2.8744 |
9.67 |
2.8174 |
10.82 |
2.7363 |
11.51 |
[0054] The amount of 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]benzo[b]thiophene
hydrochloride present in the crystalline material is about 87.1%, as determined using
the high performance liquid chromatography (HPLC) assay described below. The amount
of 1,2-dichloroethane present in the crystalline material is about 0.55 molar equivalents,
as determined by proton nuclear magnetic resonance spectroscopy.
Preparation 6
6-Hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]-benzo[b]thiophene
Hydrochloride 1,2-Dichloroethane Solvate
(Crystal Form I)
[0055] A mixture of the compound prepared as described in Preparation 2 (15 g) and dimethylformamide
(0.2 mL) in 1,2-dichloroethane (250 mL) was cooled to 0°C. Phosgene (8.25 mL) was
condensed in a cold, jacketed addition funnel (-10°C), and added to the cold mixture
over a period of two minutes. The resulting mixture was heated to about 47°C. After
about two and one half hours, the reaction was assayed by HPLC for completion. Additional
phosgene may be added to drive the reaction to completion. Excess phosgene was removed
by vacuum distillation at 30-32°C and 105-110 mm Hg.
[0056] After about three to four hours, the reaction solution was treated with the compound
prepared as described in Preparation 1 (13.52 g). The resulting solution was cooled
to 0°C. Boron trichloride (12.8 mL) was condensed in a graduated cylinder, and added
to the cold reaction mixture. After eight hours at 0°C, the reaction solution was
treated with additional boron trichloride (12.8 mL). The resulting solution was heated
to 30°C. After 15 hours, the reaction was monitored for completion by HPLC.
[0057] A mixture of ethanol and methanol (125 mL, 95:5, 3A) was heated to reflux, and treated
with the reaction solution from above over a 60 minute period. Upon complete addition,
the acylation/demethylation reaction flask was rinsed with additional ethanol (30
mL). The resulting slurry was allowed to cool to room temperature with stirring. After
one hour at room temperature, the crystalline product was filtered, washed with ethanol
(75 mL), and dried at 40°C
in vacuo to give 25.9 g of the title compound. The X-ray powder diffraction pattern is reported
in Table 1. Melting point 261°C.
Potency: 87.1%
1,2-Dichloroethane: 0.55 molar equivalents (
1H NMR)
Preparation 7
6-Hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]-benzo[b]thiophene
Hydrochloride Chlorobenzene Solvate
(Crystal Form 3)
[0058] A solution of the compound prepared as described in Preparation 1 (2.92 grams) and
the acid chloride prepared as described in Preparation 4 (3.45 grams) in chlorobenzene
(52 mL) was cooled to about 0°C. The cold solution was treated with boron trichloride
(2.8 mL). The resulting mixture was mechanically stirred at about 0°C. After three
hours, additional boron trichloride (2.8 mL) was added, and the reaction mixture was
allowed to warm to room temperature. After about 16-20 hours, the reaction mixture
was cooled to 0°C. The cold reaction was quenched by the slow addition of ethanol
(26 mL) over 30 minutes. During the addition of the alcohol, a crystalline solid formed.
Upon complete addition of the alcohol, the resulting mixture was stirred at room temperature
for one hour. The crystalline solid was removed by filtration, washed with cold ethanol
(25 mL), and dried
in vacuo at 40°C to give 5.94 grams of the title compound as a yellow solid. The X-ray powder
diffraction pattern is identical to that reported in Table 2. Melting point 247°C.
Potency: 78.6%
Chlorobenzene: 12.3% (HPLC)
Table 2.
X-ray Diffraction Pattern for Crystal Form III. |
d-line spacing (Angstroms) |
I/I o (x100) |
14.3518 |
7.24 |
10.3335 |
6.17 |
8.8305 |
4.29 |
7.9475 |
38.16 |
6.5904 |
64.25 |
6.2848 |
6.52 |
5.6048 |
28.06 |
5.4107 |
100.00 |
5.1544 |
11.26 |
5.0493 |
53.26 |
5.0224 |
46.11 |
4.8330 |
76.94 |
4.7694 |
34.23 |
4.6461 |
50.22 |
4.5754 |
38.61 |
4.4953 |
72.65 |
4.3531 |
49.15 |
4.2940 |
41.64 |
4.2425 |
35.75 |
4.1856 |
21.63 |
4.1338 |
9.47 |
4.0793 |
12.69 |
3.9960 |
18.50 |
3.9037 |
9.03 |
3.7854 |
40.39 |
3.7521 |
54.16 |
3.6787 |
28.60 |
3.6509 |
17.96 |
3.5444 |
31.72 |
3.4679 |
41.55 |
3.3899 |
7.69 |
3.3101 |
5.72 |
3.2561 |
7.42 |
3.1784 |
15.19 |
3.0445 |
11.17 |
3.0146 |
8.94 |
2.9160 |
11.89 |
2.8217 |
18.23 |
2.7500 |
12.06 |
2.6436 |
9.65 |
2.6156 |
6.97 |
[0059] The amount of 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl]benzo[b]thiophene
hydrochloride present in the crystalline material is about 78.6%. The amount of chlorobenzene
present in the crystalline material is about 12.3%, as determined by HPLC.
Preparation 8
6-Hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)-benzoyl]benzo[b]thiophene
Hydrochloride
[0060] A solution of sodium hydroxide (0.313 g) in methanol (10 mL) was diluted with additional
methanol (40 mL) and water (10 mL). This solution was treated with the compound prepared
as described in Example 5 (4.0 g). The resulting solution was extracted with hexane
(2 x 50 mL) to remove the chlorobenzene. The methanolic phase was treated with 2 N
hydrochloric acid (4 mL), producing a crystalline slurry. After one hour, the crystalline
product was filtered, washed with methanol (5 mL), and dried at 60°
in vacuo to give 2.23 g of the title compound. The X-ray powder diffraction pattern was identical
to that reported in Table 3.
Table 3.
X-ray Diffraction Pattern for Non-solvated Crystal Form. |
d-line spacing (Angstroms) |
I/Io (x100) |
13.3864 |
71.31 |
9.3598 |
33.16 |
8.4625 |
2.08 |
7.3888 |
7.57 |
6.9907 |
5.80 |
6.6346 |
51.04 |
6.1717 |
29.57 |
5.9975 |
5.67 |
5.9135 |
9.87 |
5.6467 |
38.47 |
5.4773 |
10.54 |
5.2994 |
4.74 |
4.8680 |
4.03 |
4.7910 |
5.98 |
4.6614 |
57.50 |
4.5052 |
5.75 |
4.3701 |
9.03 |
4.2516 |
69.99 |
4.2059 |
57.64 |
4.1740 |
65.07 |
4.0819 |
12.44 |
3.9673 |
22.53 |
3.9318 |
100.00 |
3.8775 |
9.07 |
3.7096 |
33.38 |
3.6561 |
21.65 |
3.5576 |
3.36 |
3.5037 |
7.97 |
3.4522 |
18.02 |
3.4138 |
4.65 |
3.2738 |
10.23 |
3.1857 |
8.90 |
3.1333 |
6.24 |
3.0831 |
9.43 |
3.0025 |
12.13 |
2.9437 |
4.96 |
2.8642 |
7.70 |
2.7904 |
11.95 |
2.7246 |
3.05 |
2.6652 |
3.32 |
2.5882 |
7.30 |
[0061] The amount of 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinylethoxy)benzoyl)benzo[b]thiophene
hydrochloride present in the crystalline material is at least 95%.
[0062] This non-solvated crystalline form is particularly preferred for use in the manufacture
of pharmaceutical compositions.
Example 1
Preparation Preparation of Amorphous Form
[0063] The amorphous material of the instant invention was prepared by dissolving 5 g of
crystalline raloxifene hydrochloride in 300 ml of methanol and 22.5 ml of water. The
amorphous material was recovered by spray drying the solution using a Buchi Model
190 Mini spray dryer under the following conditions: equilibrium inlet temperature:
84 °C; equilibrium outlet temperature:
60 °C; approx. spray rate: 2.5 ml/min.; aspirator setting: 20; air flow indicator:
500-600; atomization pressure: 35 psi. The process was completed in 2 hours and 10
minutes.
[0064] The material recovered after spray drying was observed under a polarized light microscope
to determine if the product was birefringent. No birefringence was observed, and the
material was considered to be amorphous.
[0065] Table 4 provides comparative solubility data in water between the crystalline and
amorphous material:
Table 4
Form |
Solubility (mg/ml) |
Temp., °C |
crytalline |
0.08 |
room temperature |
amorphous |
42.2 |
room temperature |
amorphous |
120 |
37 °C * |
[0066] The amorphous material was also made as a complex with povidone, with ratios of raloxifene
HCl to PVP as follows: 9:1, 3:1, and 1:1 (w/w). Complexes with hydroxypropyl-b-cyclodextrin
(HPBCD) were also prepared, with a ratio of raloxifene HCl to HPBCD of from 1:1 to
1:4 (w/w). These were added to increase solubility and to prevent any potential crystallization
of the material, for example, which may or may not occur when a supersaturated solution
was prepared from the amorphous form. Some lots were recovered as crystalline material,
or the material was converted to a crystalline form within about a week or 10 days
after preparation. The lots recovered as amorphous material which did not crystallize
within about 10 days were observed to remain amorphous.
Example 2
Bioavailability Study
[0067] The extent and rate of absorption of the crystalline and amorphous forms of raloxifene
HCl was determined. The two forms of the compound were formulated in a PEG vehicle
as follows:
Component |
% by weight |
Polyethylene glycol 1450 |
70 |
spray dried lactose |
1.5 |
colloidal silicon dioxide |
1.5 |
polysorbate 80 |
2.0 |
raloxifene HCl |
25 |
Six dogs were dosed as follows: three dogs received the amorphous form, while three
dogs received the crystalline form, both at a dose of 4mg/kg. Plasma levels of the
two compound forms were then determined over a 10 hour period. This study indicated
greater bioavailability with the amorphous form.
[0068] The following discussions illustrate methods of use for the compound of formula I
in experimental models or in clinical studies. These examples are for the purposes
of illustration and are not meant to be limiting in any way.
A. Osteoporosis:
[0069] Experimental models of postmenopausal osteoporosis are known in the art. Germane
to this invention is the ovariectomized rat model which is provided in U.S. 5,393,763.
The compound of formula I would be active in this model and would demonstrate an effective
treatment or prevention of bone loss due to the deprivation of estrogen.
[0070] An additional demonstration of the method of treating or preventing osteoporosis
due to estrogen deprivation would be as follows: One hundred patients would be chosen,
who are healthy postmenopausal women, aged 45-60 and who would normally be considered
candidates for estrogen replacement therapy. This includes women with an intact uterus,
who have had a last menstrual period more than six months, but less than six years.
Patients excluded for the study would be those who have taken estrogens, progestins,
or corticosteroids six months prior to the study or who have ever taken bis-phosphonates.
[0071] Fifty women (test group) would receive 15-80 mg of a compound of formula I, for example,
Formulation 1 (above), per day. The other fifty women (control group) would receive
a matched placebo per day. Both groups would receive calcium carbonate tablets (648
mg) per day. The study is a double-blind design. Neither the investigators nor the
patients would know to which group each patient is assigned.
[0072] A baseline examination of each patient includes quantitative measurement of urinary
calcium, creatinine, hydroxyproline, and pyridinoline crosslinks. Blood samples are
measured for serum levels of osteocalcin and bone-specific alkaline phosphatase. Baseline
measurements would also include a uterine examination and bone mineral density determination
by photon absorptiometry.
[0073] The study would continue for six months, and each of the patients would be examined
for changes in the above parameters. During the course of treatment, the patients
in the treatment group would show a decreased change in the biochemical markers of
bone resorption as compared to the control group. Also, the treatment group would
show little or no decrease in bone mineral density compared to the control group.
Both groups would have similar uterine histology, indicating the compound of formula
I has little or no utrotrophic effects.
B. Hyperlipidemia:
[0074] Experimental models of postmenopausal hyperlipidemia are known in the art. Germane
to this invention is the ovariectomized rat model which is detailed in U.S. 5,464,845.
Estrogenicity may further be assessed by evaluating the response of eosinophil infiltration
into the uterus. A demonstration of the method of treating hyperlipidemia due to estrogen
deprivation would be as follows: One hundred patients would be chosen, who are healthy
postmenopausal women, aged 45-60, and who would normally be considered candidates
for estrogen replacement therapy. This would include women with an intact uterus,
who have not had a menstrual period for more than six months, but less than six years.
Patients excluded for the study would be those who have taken estrogens, progestins,
or corticosteroids.
[0075] Fifty women (test group) would receive 15-80 mg of a compound of formula I, for example,
using Formulation 1, per day. The other fifty women (control group) would receive
a matched placebo per day. The study would be a double-blind design. Neither the investigators
nor the patients would know to which group each patient is assigned.
[0076] A baseline examination of each patient would include serum determination of cholesterol
and tri-glyceride levels. At the end of the study period (six months), each patient
would have their serum lipid profile taken. Analysis of the data would confirm a lowering
of the serum lipids, for example, cholesterol and/or tri-glycerides, in the test group
versus the control.
[0077] From the foregoing, it will be seen that this invention is one well adapted to attain
all the ends hereinabove set forth together with advantages that are inherent to the
invention. It will be understood that certain features and subcombinations are of
utility and may be employed without reference to other features and subcombinations.
This is contemplated by and within the scope of the claims. Because many possible
embodiments can be made of the invention without departing from the scope thereof,
it is to be understood that all matter herein set forth is to be interpreted as illustrative
and not in a limiting sense.